Electrical resistor



H. C. GORDEN ELECTRICAL RESISTOR Dec. 29, 1953 2 Sheets-Sheet 1 FiledJan. 7, 1952 Enry a arden;

Dec. 29, 1953 H, c, GQRDEN 2,664,487

ELECTRICAL RESISTOR Filed Jan. 7, 1952 2 Sheets-Sheet 2 16 4 i if .18 x15 50 I 26 28 am J1 26' Bill/4:25:25 :EsiiiW/l/IJ; 51 W .51

\\\\\\\\\\\\\\\\\\\\\\ &\\\\\\9 l 214972237 6. Garden Patented Dec. 29,1953 UNITED STATES PATENT OFFICE ELECTRICAL RESISTOR Henry G. Gordon,Los Angeles, Calif., assignor to Gorman Manufacturing Corporation, LosAngeles, Calif., a corporation of California Application January 7,1952, Serial No. 265,249

9 Claims. 1

This invention relates to an electrical resistance device fordetermining the amount of current flowing in a circuit for any givenvoltage applied to the circuit and has as its primary object theprovision of a precision resistor of the type embodying an electricallyconductive coil wound on a spool and encased in a housing which spooland housin are formed of an electrically insulating material; theinvention residing in a construction and arrangement of parts and in amode of assemblage whereby the device may be readily and economicallymanufactured and whereby a resistor will be produced that ischaracterized by its compactness and lightness and its affordin amaximum amount of performance with the smallest amount of weight andsize, by its capability of withstanding great thermal change from hot tocold and vice versa, and by its immunity to the deteriorating eiiects oflong exposure to adverse climatic conditions.

Another object is to provide a construction in the resistor which isparticularly applicable to and facilitates the production of resistorsof extremely small caliber particularly suitable for use in electronicsystems such as sets used in radio and radar and television equipmentand the like. Another object is to provide a construction forfacilitating the positioning of a resistance coil on a spool togetherwith laterally extending rigid terminals at the ends of the coil,arranging the assembly within a cylindrical shell and eflfectivelysealing the coil within the shell.

Another object is to provide a wire-wound precision resistor of theabove character which when constructed of extremely small or minute sizewill be quite strong and accordingly not subject to easy breakage anddamage as is the case with the fragile small resistors now generally onthe market, and which with the characteristics above set forth isrendered especially applicable for use in aircraft, air-borne missilesand equipment calling for maximum resistor performance under extremevariations in altitude ranging up to tremendous heights, as well asextreme variations in temperature as for example from minus 70centigrade to plus 200 centigrade, and where extreme lightness in weightand small dimension is a desideratum.

A further object is to provide a construction in a resistor of the typespecified whereby the terminals of the resistor coil may be either fromthe side or from the ends of the device according to requirements and tofacilitate application of the resistor in a particular piece ofequipment.

With the foregoing objects in view together with such other objects andadvantages as may subsequently appear, the invention resides in theparts and in the combination, construction and arrangement of partshereinafter described and. claimed, and illustrated by way of example inthe accompanying drawing in which:

Fig. 1 is a perspective view of a preferential form of the resistor;

Fig. 2 is a view in longitudinal section and partly in elevation of theresistor shown in Fig. 1;

Fig. 3 is a perspective view of the resistor spool and coil assembly asremoved from its housing or shell;

Fig. is a view in longitudinal section of the r assembly shown in Fig.3;

Fig. 5 is a perspective view with portions broken away of a shell forreceiving the assembly shown in Figs. 3 and 4 for encompassing andhousing the resistor coil;

Fig. 6 is a view in section and elevation illustrating the manner ofassembling the coil assembly in Figs. 3 and 4 within the shell depictedin Fig. 5;

Fig. 7 is a view illustrating the parts of the spool and coil assemblyas separated;

Fig. 8 is a view in longitudinal section illustrating a modified form ofthe spool and coil assembly;

Fig. 9 is a view in vertical section showing another form of theinvention;

Fig. 10 is a view in side elevation depicting a further form of theinvention;

Fig. 11 is a view in horizontal section taken on the line llll of Fig.10, with the coil removed; and

Fig. 12 is a view in vertical section and elevation taken on the linelE-l 2 of Fig. 11.

Referring to the drawing more specifically A indicates a cylindricalshell which is open at least at one of its ends and is provided at anend thereof with a wall H having an axial circular opening it which wallmay be formed integral with the shell A as shown in Figs. 1, 2, 5, and 6or may be formed independent of the shell and subsequently appliedthereto to close one end thereof as shown in Figs. 9, 10 and 11.

In the construction shown in Figs. 1, 2, 5, 6 and 10 the cylindricalshell A is formed with a slot l2 adjacent its forward or open end andwith a slot I l adjacent its other end closed by the wall I0.

The shell A is designed to receive a spool and coil assembly Bparticularly shown in Figs. 3 and 4 which assembly embodies a tubularcylindrical core 15 and which core is insertable in the open 3 end ofthe shell A with the inner free end portion thereof inserted in theopening I I and snugly engaged with the portion of the end wall Isurrounding said opening as shown in Figs. 2, 9 and 11.

An annular flange i6 is formed on the outer end of the cylindrical coreI5, the marginal portion of which is formed to abut the outer open endof the shell A and being formed with a reduced inner marginal portion I?dimensioned to snugly abut the inner peripherial portion of the shell Aadjacent the outer end thereof.

The shell A with its end wall lcll andalso the spool comprising the corewith its'end "flange I6, are formed of suitable insulating materfialsuch for example as a plastic compositionicoinposed of a phenolicthermo-setting compound, a cellulose product, a phenol resin product,nylon, pressed fibers, rubber and the like; being preferably molded of anon-hygroscopic ,heat resistant compound, with high dielectric strengthand very low co-efiicient of expansion and highly resistantto thermalshock; the compound most suitably employed being onethat can withstand.over 200 centigrade and at least 1ninus 70 centigrade.

A resistance coil composed of a suitable Wire formed of an electricalconductive material of suitable resistance quality such as nichromewire,

:is wound into a cylindrical coil C comprising a requisite number ofconvolutions imposed on the core l5. This coil C may either be wounddigrectly on the core I 5 or may be wound on a suitable arbor andthereafter telescoped on the core. lhe terminals a--b of the wireforming cylindrical coil C may be threaded throughopenings l8 and I9 inthe core I5 as shown in Fig. 8, or may be directed through the slots I2and M in the shell A when, assembling "the element B therein, but thepresent invention contemplates the employment of a more substantialconstruction, which in the construction shown in'Figs.

l to Tinclusive consists in providing the device with a pair ofrigidelectr'ically conductive terminalposts which project through the,slots ;I2- -I4; the post D being forinedon the margin of an annulusencircling the core I5 .ibetween tlie fiange it and the adjacent end ofthe coil C to which-one end a of the wire forming the coil C isatlixedin suitable fa hion, preferably by welding. The post E is formed on themargin of 1 an annulus 2i encircling theinner end portion of the core I5and to which the other terminal b of the wire forming coil C is affiXedas by welding. In connecting the ends ab of the coiled wire to theannuli- 20--2I strain loops 2223 are for e in such ends between theirpoint of attachment to the annuli and the ends of the coil C.

Suitable insulating gasketsid. and are. provided to overlie the innerfacesof the annular members 26 and 21 and the end faces of, thecylindrical coil C.

In the construction and assemblageof the .resistor as shown in- Figs. 1to '7 the spool and c'oil assembly B isv made asshown in Fig. 4; the

annulusifi being first positioned on-the core I5 to abut the flange ISwith the gasket. 24 abutting and covering the inner face of the annulus20. The coil C is then provided on the core I5 with one end portion ofthe resistance. Wire thereof slightly extended from thecoil and formedinto the strain loop 22 the outer endof which is'a'ffixedj to the;annulusfifl as before stated. I The other end portion of the resistancewire of 'the into the coil C is then formed into the strain loop 23which is then welded to the annulus 2I which annulus is then positionedon the free end por tion of the core I5 in loose relation to the coreand coil with the gasket 25 interposed between the annulus 2| and theadjacent end of the coil C. The assembly B and shell A are then puttogether by inserting the core and coil in the open end of the shell Aas shown in full lines in Fig. 6 with the outer end of the post Epresented to the slot I l. The core and coil are then advanced into theshell with the outer end portion of the post E passing through the slotI4,

as indicated in dotted lines in Fig. 6; the core and shell being thusadvanced until the free end of the core I5 is moved into the opening IIand disposedin close abutting contact with the marginal portion of theend wall In surrounding the openin ii and with the anulus 2| abuttingthe end wall It and with the coil cylinder C abutting the gasket 24 asindicated in broken lines in Fig. 6. The flange IE will then be disposedin its engaged position with the shell A and with the post D arranged inthe slot I2.

The posts D and E will then pro'ect radially from the shell A to afiordconnections for electrical conductors with which the resistor is to beassociated.

.Where the assembly B is formed as shown in Fi g. 8, that is without theradial posts D and E and with the terminals a and b of the coil Cleading from the ends of the core l5, the shell jAis applied over theassembly and disposed with its open with the applying the fr'eeend wallIt theouter end of the core IE will be received in the opening II andengagedwith the wall iii.

In the construction shown in Fig. Qthe res stor is provided with copperwire terminals 2526 which lead into the open ends of the core i5 andthrough openings I8'-I9' in the core and have flattened ends 28-28 towhich the termi- Inals of the wire coil C are attached by weld joints 0.Metal grommets 29-29 are fitted in the ends of the core and have holes3ll-3II through which 7 the terminals 23- 45 extend, which terminals areanchored in the romtrets by solder plugs 3l-3i appliedin a molten statein the open outer end of the grommets against fiber plugs 3 l 3i aftercompleting the assembl y. The plugsiSL-Si also serve to seal the holes3ii 3fl.lead ing to theopenings I 8- i 9' thus sealingthe latter.

,In the construction shown in Figs. 10-12 wherein the end wall Ill isassembled on the shell A, the innerface of the wall I 0 as well as thatof the flange H3, is formed with an annular reeess 32in which the annuli2! and 20 are seated and arranged with the terminals E and D there- 'onextehded radially from the end wall and a flange through the slots I2and I4 of the shell;

v The'iree end wall it, likethe flang IS form closuresiorltheends' ofthe cylindrical shell A and are snugly fitted to the latter "as" is tlicon- 5 nection between the core and the end wall I 0, and if desired thejoints between the parts may be sealed by a suitable adhesive. The slots82-!4, and openings l8-|9 and I8-l9' are sealed around the terminalsextending therethrough.

I claim:

An electrical resistor comprising a cylindr'cal shell open at one endand having an end wall at its other formed with an axial circularopening, a spool embodying a resistance coil receiving core insertablein the open end of said shell with an end thereof inserted in saidopening in snug engagement with th portion of end wall surrounding saidopening, an inteannular ilange on the other of said core abutting theopen end said shell having a reduced inner marginal portion abutting theinner peripheral portion of said shell adjacent the open end thereof, acylindrical coil of resistance wire encompassing said core, andterminals on coil leading exteriorly of said shell.

electrical comprising a cylindrical shell open at one end having an endwall at its other end formed with an axial circular opening, said shellbeing formed with a slot adjacent end thereof, a spool embodying acylindrical core having a free end and formed with an integral annularflange at its other end, a cylindrical coil of resistance wireencompassing said core having terminals leading from said coil; spooland coil being arranged within said shell with said flange tightlyabutting the open end of the shell and with the free end of said coreextending into said end Wall opening snug rent with the portion of theend wall surrounding said opening, and with said terniin extendingthrough the slots in said shell. The structure c lied for in claim 2 inwhich the terminals each comprise a rigid electrically conductiveannulus encircling the core adjacent end of the coil and connected tothe latter a post on and leading from said annulus and extending fromthe latter through one of the slots n said shell and pr ing from thelatter.

4?. in electrical resistor comprising a cylindrical shell having an openend and a closed end. with closed end formed with an axial circularopening, said shell having a slot adjacent each end thereof, a spoolembodying a cylindrical core having a flanged end and a free end, ametallic annulus encompassing each of the ends of said core, a post oneach annulus projecting through of the slots in said shell, a coil ofresistance wire encompassing said core having ends one or which iselectrically connected to one annulus and the other of which iselectrically connected to th other annulus; said core being arrangedwithin said shell with its flanged end 6 engaging the open end of saidshell and with its free end engaged with the opening in the shell endwall.

5. The structure called for in claim l in which said shell and spool areformed of a non-hygroscopic heat resistant material with high dielectrictrength and very low co-efficient of expansion and highly resistant tothermal sh ck.

6. Th st ucture called for in claim a in which the resistance wirecomprises nicrome wire and which the ends of said Wire are connected totheir respective annulus through a strain loop and by a weld joint.

7. An electrica resistor comprising a cylindrical shel having open ends,an end wall closing one end of said shell formed With an axial circularopening, spool and coil assembly in said shell comprising a tubular corehaving open ends and formed with a flange on one of its ends seated onand engaging one end of said cylindrical shell, said core having a freeend extending into the opening in said end wall and snugly engaged bythe latter, a coil of resistance wire encompassing said core havingterminals, said terminals extending through said core and out the openends thereof.

8. The structure called for in claim 7 together with metal grommetswhich are inserted in the open ends of the core through which theterminals lead, and solder plugs in said grommets anchoring theterminals therein.

9. An electrical resistor comprising a cylindrical shell, an end wallclosing one end of said shell and provided with an axial opening, aspool and coil assembly in said shell comprising a tubular core havingopen ends and a flange on one of its ends seated on and engaging theother end of said cylindrical shell for closure thereof, the other endof said cor being free and extending into the opening in said end walland snugly engaged by the latter, a coil of resistanc wire encompassingsaid core having terminals, said terminals embodying annuli inset insaid flange and end wall and posts extending from the annuli throughsaid shell and projecting therefrom, and insulation gaskets interposedbetween said annuli and the ends of said coil.

HENRY C. GORDEN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,387,522 Thornton Aug. 16, 1921 l.,7i5,872 Stickney Feb. 4,1930 1,872,068 Brown Aug. 16, 1932 2,243,047 Addy et a1. July 8, 19412,547,465 Mitchell et a1 Apr. 3, 1951 2,556,973 Nickells June 12, 1951

